Patents by Inventor Evert J. Rijkhof

Evert J. Rijkhof has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Filtration apparatus
    Patent number: 5093000
    Abstract: A filtration apparatus for filtering water has a filter cloth which is supported on one side by support means against the pressure applied by water being filtered. During cleaning by reverse flow of water the cloth billows away from said support and cleaning means contact the billowed out filter cloth to clean it. To improve the cleaning effect, the cleaning means comprise a movable plate which is contacted by a region of said billowed out filter cloth during the reverse flow. The plate has at least one aperture at which said reverse flow occurs, and the aperture is moved relative to the filter cloth by movement of the plate.
    Type: Grant
    Filed: October 22, 1990
    Date of Patent: March 3, 1992
    Assignee: Esmil Water Systems BV
    Inventors: Evert J. Rijkhof, Johannes P. P. Tholen
  • Preparation of quaternary ammonium hydroxides
    Patent number: 5089096
    Abstract: A process for the preparation of a quanternary ammonium hydroxide, which comprises electrolyzing a quaternary ammonium halide in a divided electrolysis cell wherein the anode material is selected from iron, nickel, zinc, molybdenum and manganese, and an electrolysis cell specifically adapted for use in the process.
    Type: Grant
    Filed: August 31, 1990
    Date of Patent: February 18, 1992
    Assignee: Shell Research Limited
    Inventors: Evert J. Rijkhof, Johannes P. P. Tholen, Hendricus J. H. Van Der Maas, Gosse Boxhoorn